radiators on when thermostat at zero

[garageman]

System is Baxi bermuda back boiler , feed and expansion tank in loft so presume pumped system.
With cenral heating and hot water on but room thermostat at zero the radiators still come on, the worst one being the kitchen unit which is only rad without thermostatic valve. Is thermostat faulty or have i got other problem.

 

[gasmick2]

hi just saw your post sounds like you have a gravity hot water and pump on the heating 2 things it could be the rads can work on gravity and if the system has good circulation sometimes i have seen all the rads getting hot all over the house thats why a non return valve was fitted in the flow to the heating it stops hot water rising,
the other thing is the stat points might be welded together as they sometimes arc over the years old stats usually click on turning up and turning down its only modern ones that do not